Safety connection for taps and chucks.



No. 881,075. PATENTED MAR. 3, 1908; J. HOSKING.

SAFETY CONNECTION FOR TAPS AND GHUCKS.

APPLICATION FILED MAR.18, 1907.

I Jw foa/fizky UNITED s'rarrns PATENT orrron.

JOHN noskme, or

CLAREMONlYNElN HAMPSHIRE, ASSIGNOR OF ONE-HALF TO JERE (T. DYFRESNE. OFCLAREMQNT. NEW HAMPSHIRE.

SAFETY CONNECTION FOR TAPS AND CHUCKS.

Specification of Letters Patent.

Patented March 3, 1908.

Application filed. h'larch 18, 1907. Serial No. 362.958.

citizen of the United States, residing at Claremont, in the county ofSullivan and State of Xew Hampshire, have invented new and usefulImprovements in Safety Connection for Taps and Chucks, of which thefollowing is a specification.

This invention relates to a tap chuck and particularly to means forseparably holding the tap in the socket portion of the chuck. Inordinary chuck organizations with which taps are used, the tap isrigidly fasi'sbeing done.

tened to the driving spindle, and in consequence, when'employed fortapping, it becomes necessary, as the tap approaches the bottom of thehole to so regulate the movement of the driving mechanism as to preventthe tap from striking the bottom and receiv' ing the full powertransmitted to the'spindle or shank, which would result in breaking thetap, or, if the tap is of sufficient strength to resist breakage, wouldinjure the driving mechanism or the material on which the work Toobviate these difficulties the improved tap chuck is provided with asafety pin to engage the'tap shank, said pin being preferably formed ofsoft steel wire and adapted to be sheared off or broken when the tapreaches the bottom of the hole and thus prevent injury to the tap chuckand-the driving mechanism as well. as the material operated upon. It isproposed to use safety pins for connecting the taps to the chucks havingvariations in diameter to correspond to the sizes of the taps. Theadvantage of the use of a plurality of pins of different diameters willbe obvious in view of the fact that more power is required to operate aone-inch tap, for instance, than a tap of smaller dimensions, and if thesmaller pin was used with the larger tap it would be without practicalservice in view of the fact that it would shear or break at anundesirable time or before the tap had completed its work. The inventionalso contemplates details of construction which will be more fullyhereinafter specified.

In the drawing: Figure 1 is a perspective view of a tap chuck embodyingthe features of the invention and showing the parts separated. Fig. 2 isan. elevation, partly in section, of a 'tap chuck showing a tap securedtherein by the improved safety pin. Fig. 3

. is a horizontal section on the line 3-3, Fig.

2. 4 shows detail views of safety pins having varying diameters.

Similar characters of reference are employed to indicate correspondingparts in the several views.

The numeral 1 designates the shank or stem of the chuck, to the upperend of which suitable driving means may be applied. At the lower end ofthe chuck stem or shank is a socket 2 in which is removably fitted abushing 3, the latter having an angular opening 4 to receive thecorrespondingly shaped shank of a tap 5. The upper portions'of thesocket and bushing are formed with a plurality of diametrically arrangedopenings 6 to receive pins 7, the openings 6 and pins 7 being of(lifferent sizes ordiameters. The pins 7 serve as safety pins forconnecting the bushing carrying the tap to the socket 2 so that the saidbushing and tap will rotate with thestem or shank 1 and the socket, andthe several pins are made just long enough to terminate at theiropposite ends flush with the outer surface of the socket. To permit thepins 7 to be readily inserted through the socket 2 and bushing 3 andalso to retain the pins in inseparable relation to the parts just mentioned, a movable collet 8 is provided and is adapted to cover thesocket, as clearly shown by Fig. 2. This collet 8 is of a length equalto that of the socketand has an upper in turned flange 9 which snuglyembraces the shank or stern l. The collet is readily movable over theshank or stem 1 as shown by Fig. 1, and fits the parts-to which it isapplied with sufficient tightness to remain in the position desired overthe socket during the opera t-ion of the tap.

The safety pins 7 are preferably formed of soft steel wire, and each pinhas a resisting strength sufficient to withstand. breakage or separationduring operation of the tap and before the latter reaches the bottom orterminal of the hole. As soon, however, as the taps of various sizesheld by the pins of relative diameters in the manner disclosed by Fig.2, reach the bottom of the holes, each been inserted through the socketand bushing the collet may be again readjusted in normal position.

The improved safety means will be foundexceptionally advantageous andthough it has been particularly described as a plicable to a tap chuckand tap, it will be unrv erstood that it may be used in drills and otherboring tools as Well as in stud setting implements.

The parts may also be modified in their proportions, dimensions andminor details without departing from the spirit of the inmounted in thesocket, the bushing and socket having diametric openings there through,a tap fitted in the bushing, a breakable safety in inserted intheopenings of the bushing ant socket, and means movable over the socketfor exposing the said 0 enings and also for preventing separation of t epin from the socket and bushing.

In testimony whereof I have hereunto set my hand in presence oftwosubscribing 'witnesses.

JOHN HOSKING.

